The joints included in link mechanisms used in suspensions in automobiles, ships, aircraft, and various industrial machinery mainly serve as mechanisms for positioning wheels and other members, so are required to have a certain extent of rigidity with respect to application of force from these members.
As an example of a link including such a joint, a vehicular-use I-suspension arm comprised of a main body part (rod) made of a steel sheet formed into a tubular shape and a pair of connecting parts fastened to the two end parts of this main body part is known (see Japanese Patent Publication No. 2010-76473A). One of the connecting parts is usually a bracket-type joint. This joint includes a base part connected to the rod end part and a pair of side parts extending from the outermost parts of the base part in the rod width direction to the opposite sides from the rod. Note that, the base part and the side parts are connected and fastening holes are formed in the side parts of the joint.